WO2017084907A1

WO2017084907A1 - Process for converting a feedstock comprising a lignocellulosic biomass using a polyoxometalate salt comprising nickel and tungsten or nickel and molybdenum

Info

Publication number: WO2017084907A1
Application number: PCT/EP2016/076882
Authority: WO
Inventors: Emilie Brule; Etienne Girard; Audrey Bonduelle; Amandine Cabiac; Damien Delcroix; Marc Jacquin
Original assignee: IFP Energies Nouvelles
Priority date: 2015-11-17
Filing date: 2016-11-07
Publication date: 2017-05-26
Also published as: FR3043676A1; FR3043676B1

Abstract

The invention relates to a process for converting a feedstock chosen from lignocellulosic biomass and carbohydrates, alone or as a mixture, into mono- or polyoxygenated compounds, in which the feedstock is brought into contact with a catalyst comprising one or more polyoxometalate salts comprising nickel and tungsten or nickel and molybdenum and in the presence of at least one solvent, said solvent being water alone or in a mixture with at least one other solvent, under a reducing atmosphere, and at a temperature of between 50°C and 300°C, and at a pressure of between 0.5 MPa and 20 MPa.

Description

METHOD FOR TRANSFORMING A LOAD COMPRISING A BIOMASS

LIGNOCELLULOSIC USING A POLYOXOMETALLATE SALT COMPRISING NICKEL AND TUNGSTEN OR NICKEL AND MOLYBDEN

PRIOR ART In recent years, there has been a great revival of interest in the incorporation of products of renewable origin into the fuel and chemical sectors, in addition to or in substitution for products of fossil origin. One possible route is the conversion of the cellulose contained in the lignocellulosic biomass into products or chemical intermediates, such as products containing from one to six hydroxyl functions, namely n-propanol, ethylene glycol, propylene glycol, glycerol, 1,2-butanediol, 1,4-butanediol or 1,2-hexanediol.

The term lignocellulosic biomass (LBC) or lignocellulose encompasses several constituents present in varying amounts depending on its origin: cellulose, hemicellulose and lignin. Hemicellulose and cellulose constitute the carbohydrate part of lignocellulose. They are polymers of sugars (pentoses and hexoses). Lignin is a macromolecule rich in phenolic motifs. Lignocellulosic biomass, for example, refers to products derived from logging and agricultural by-products such as straw, as well as some dedicated, high-yielding crops such as miscanthus or poplar. The production of chemicals from lignocellulosic biomass can both reduce energy dependence on oil and preserve the environment by reducing greenhouse gas emissions without using resources for food uses.

The direct conversion of a charge selected from lignocellulosic biomass and carbohydrates, alone or as a mixture, into chemical products or intermediates, in particular mono- or polyoxygenated, is a particularly advantageous route. By direct transformation is meant the transformation into a step of said feedstock, optionally pretreated, to mono- or polyoxygenated valorized products. The valorization of lignocellulosic biomass or cellulose contained in the biomass by the use of different catalysts or combination of catalysts is widely described in the literature.

For example, the use of heterogeneous catalysts such as activated carbons on which nickel is deposited has been described for the transformation of lignocellulosic biomass or cellulose in the patent application WO2013 / 015990. The recovered effluent is composed of polyoxygenated compounds soluble in the reaction medium such as ethylene glycol and propylene glycol, as well as solid residues such as unconverted cellulose and lignin lignin lignin. A further difficult step of separating the solid feed conversion residues from the heterogeneous catalyst is required to recover and recycle the catalyst.

Homogeneous catalysts of the family of metal chlorides AICI ₃ or FeCl ₃ , which are soluble in the reaction medium, have been described by Zhuang, Molecules 2010, 15, 5258 to avoid this step of separating solids, but their use in a hydrothermal medium at a temperature of temperature of 200 ° C under autogenous pressure systematically generates non-valued condensation products that are called humines and which precipitate in the reaction medium.

Unexpectedly, the applicant has discovered that the contacting of a charge selected from lignocellulosic biomass and carbohydrates, alone or in combination, with at least one polyoxometalate salt comprising nickel and a metal M chosen from tungsten and molybdenum, as claimed as a homogeneous catalyst, under specific operating conditions, made it possible to selectively obtain mono- or polyoxygenated products, in particular glycols and ethylene glycol, without formation of humins and without additional separation between the residual solids at the end of the reaction may be a heterogeneous catalyst, humins, lignin and / or unconverted cellulose.

SUMMARY OF THE INVENTION

An object of the present invention is therefore to provide a process for transforming a feedstock chosen from lignocellulosic biomass and carbohydrates, alone or as a mixture, into mono- or polyoxygenated compounds, in which said feedstock is brought into contact with a catalyst comprising one or more polyoxometalate salts comprising nickel and a metal M being tungsten or molybdenum, in the presence of at least one solvent, said solvent being water alone or mixed with at least one other solvent, under a reducing atmosphere, and at a temperature of between 50 ° C and 300 ° C, and at a pressure between 0.5MPa and 20MPa, wherein, said polyoxometalate salt or salts comprising nickel and a metal M being tungsten or molybdenum, are of the general formula ( I)

Ni _x M _y O _z H _h A _a M ' _m C _c . nH ₂ 0 (I) in which

Ni is nickel and may be in the substitution position of tungsten or molybdenum or at the cation C position,

M is tungsten or molybdenum,

O is oxygen,

H is hydrogen,

A is selected from phosphorus, silicon, boron, germanium, arsenic,

M 'is a metallic element other than nickel and tungsten when M is tungsten and M' is a metallic element other than nickel and molybdenum when M is molybdenum, said metal element being preferably selected from molybdenum, tungsten, aluminum, zinc, cobalt, vanadium, niobium, tantalum, iron and copper,

• C is an organic or inorganic cation selected from protons, ammoniums, phosphoniums, alkalis, alkaline earths, transition elements from Groups 3 to 14 of the Periodic Table,

x is between 1 and 20,

is between 4 and 80,

• a is greater than or equal to 0,

m is greater than or equal to 0,

z is between 20 and 400,

h is 0 to 20,

n is 0 to 200,

• c is greater than or equal to 0,

c, a, m, h, x, y, z and n are integers or decimals when stoichiometry and salt neutrality dictate. An advantage of the invention is to provide a process for transforming a feedstock chosen from lignocellulosic biomass and carbohydrates, alone or as a mixture, which makes it possible to directly obtain mono- or polyoxygenated products while limiting formation. non-valued products such as soluble and insoluble humins, ie products of high molecular weight resulting from undesired condensation of sugars and their derivatives.

Another advantage of the present invention lies in the use of a specific homogeneous catalyst having the advantage of avoiding the implementation of an additional separation step between the residual solids at the end of the reaction, which can be a heterogeneous catalyst. , humins, lignin and / or unconverted cellulose.

Another advantage of the invention is to provide a process for transforming a feedstock chosen from lignocellulosic biomass and carbohydrates, alone or as a mixture, into mono- or polyoxygenated compounds which make it possible to obtain very good selectivity. in glycols among all mono- or polyoxygenated products. Another advantage of the invention to provide a process for transforming a feed selected from lignocellulosic biomass and carbohydrates, alone or as a mixture, into mono- or polyoxygenated compounds which make it possible to obtain a very good selectivity in terms of ethylene glycol among all mono- or polyoxygenated products.

DETAILED DESCRIPTION OF THE INVENTION

The filler treated in the process according to the invention is a filler chosen from lignocellulosic biomass and carbohydrates, alone or as a mixture, the carbohydrates being preferably chosen from polysaccharides, oligosaccharides and monosaccharides, alone or in combination. mixed. By polysaccharides we mean one or more compounds containing at least 10 covalently linked oste subunits.

Preferred polysaccharides used as filler in the present invention are selected from starch, inulin, cellulose and hemicellulose alone or in admixture. By oligosaccharides we mean one or more compounds containing from two to ten subunits of covalently linked osteos.

The term "oligosaccharide" denotes more particularly, on the one hand, a carbohydrate having the formula (C ₆ H _{10 O 5} ) n or C ₆ nH i on + 20 ₅ n ₊ 1 where n is an integer greater than 1, obtained by partial hydrolysis of starch, inulin, lignocellulosic biomass, cellulose and hemicellulose, and on the other hand a so-called mixed carbohydrate composition

(CeH! OOsUCsHf _(m C6 H _{1 0m +} 2o5 _{m +} i) _{(8n +} C5nH 2O4n ₊ i) where m and n are integers greater than or equal to 1.

The oligosaccharides are preferably chosen from oligomers of pentoses and / or hexoses with a degree of polymerization lower than that of cellulose and hemicellulose. They can be obtained by partial hydrolysis of starch, inulin, lignocellulosic biomass, cellulose or hemicellulose. Oligosaccharides are generally soluble in water.

The preferred oligosaccharides used as filler in the present invention are chosen from sucrose, lactose, maltose, isomaltose, inulobiosis, melibiose, gentiobiose, trehalose, cellobiose, cellotriose, cellotetraose and oligosaccharides. from the hydrolysis of the polysaccharides named in the previous paragraph.

By monosaccharides is meant simple sugars (hexoses, pentoses) which can be produced by complete or partial depolymerization of the polysaccharides. Preferred monosaccharides used as filler in the present invention are selected from glucose, galactose, mannose, fructose, altrose.

Lignocellulosic biomass consists essentially of three natural constituents present in varying amounts according to its origin: cellulose, hemicellulose and lignin.

Cellulose (C ₆ H _{10 O 5} ) n represents most of the composition of lignocellulosic biomass. Cellulose is a linear homopolymer composed of numerous units of D-Anhydroglucopyranose (AGU) linked together by β- (1 → 4) glycosidic bonds. The repetition pattern is the cellobiose dimer.

Cellulose is insoluble in water at ambient temperature and pressure.

The cellulose used may be crystalline or amorphous. Hemicellulose is the second most important carbohydrate after cellulose in lignocellulosic biomass. Unlike cellulose, this polymer consists mainly of pentose monomers (5-atom rings) and hexoses (6-atom rings). Hemicellulose is an amorphous heteropolymer with a lower degree of polymerization than cellulose.

Lignin is an amorphous macromolecule present in lignocellulosic compounds in variable proportions depending on the origin of the material (straw ~ 15%, wood: 20-26%). Its function is mechanical strengthening, hydrophobization and plant support. This macromolecule rich in phenolic units can be described as resulting from the combination of three monomer units of propyl-methoxy-phenol type. Its molar mass varies from 5000 g / mol to 10000 g / mol for hardwoods and reaches 20000 g / mol for softwoods.

The lignocellulosic raw material may advantageously consist of wood or vegetable waste. Other non-limiting examples of lignocellulosic biomass material are farm residues such as, for example, straw, grasses, stems, cores, or shells, logging residues such as thinning products , bark, sawdust, chips, or falls, logging products, dedicated crops (short rotation coppice), residues from the agri-food industry such as residues from the cotton industry , bamboo, sisal, banana, maize, panicum virgatum, alfalfa, coconut, or bagasse, household organic waste, waste wood processing facilities and woods used construction, pulp, paper, recycled or not.

The lignocellulosic biomass can advantageously be used in its raw form, that is to say in all of these three constituents cellulose, hemicellulose and lignin. The raw biomass is generally in the form of fibrous residues or powder. It can also advantageously be milled or shredded to allow its transport.

The lignocellulosic biomass feed may advantageously also be used in its pretreated form, that is to say in a form containing at least one cellulosic part after extraction of lignin and / or hemicellulose. The biomass is preferably pretreated to increase the reactivity and accessibility of the cellulose within the biomass prior to processing. These pretreatments are of a mechanical, thermochemical, thermomechanical-chemical and / or biochemical nature and cause the decystallinization of the cellulose, a decrease in the degree of polymerization of the cellulose, the solubilization of the hemicellulose and / or lignin and / or cellulose or partial hydrolysis of hemicellulose and / or cellulose following the treatment.

Pretreatment prepares the lignocellulosic biomass by separating the carbohydrate portion of the lignin and adjusting the size of the biomass particles to be treated. The size of the biomass particles after pretreatment is generally less than 5 mm, preferably less than 500 microns. Catalysts

According to the invention, said filler is brought into contact with a catalyst comprising one or more salts of polyoxometalates comprising nickel and a metal M being tungsten or molybdenum, corresponding to the general formula (I), in the presence of at least one solvent, said solvent being water alone or mixed with at least one other solvent, under a reducing atmosphere, and at a temperature of between 50 ° C. and 300 ° C., and at a pressure of between 0.5MPa and 20MPa.

According to the invention, said catalyst (s) is (are) chosen from polyoxometallate salts comprising nickel and a metal M being tungsten or molybdenum, corresponding to the general formula (I)

Ni _x M _y O _z H _h A _a M ' _m C _c . nH ₂ 0 (I)

in which

• Ni is nickel,

M is tungsten or molybdenum, preferably tungsten,

• O is oxygen,

• H is hydrogen,

A is chosen from phosphorus, silicon, boron, germanium and arsenic, preferably from phosphorus and silicon,

M 'is a metallic element other than nickel and tungsten when M is tungsten and M' is a metallic element other than nickel and molybdenum when M is molybdenum, said metal element being preferably selected from molybdenum, tungsten, aluminum, zinc, cobalt, vanadium, niobium, tantalum, iron and copper, C is an organic or inorganic cation selected from protons, ammoniums, phosphoniums, alkalis, alkaline earths, transition elements of Groups 3 to 14 of the Periodic Table, preferably C is nickel, x is included between 1 and 20, preferably between 1 and 10,

y is between 4 and 80, preferably between 4 and 50,

a is greater than or equal to 0, preferably equal to 0, 1 or 2,

m is greater than or equal to 0,

z is between 20 and 400, preferably between 20 and 200,

h is 0 to 20, preferably 0 to 10,

N is between 0 and 200, preferably between 0 and 100,

c is greater than or equal to 0,

c, a, m, h, x, y, z and n are integers or decimals when stoichiometry and salt neutrality dictate.

Ni may advantageously be in the substitution position of the metal M being tungsten or molybdenum or cation C position.

Advantageously, said nickel-containing polyoxometalate salt (s) and a metal M being tungsten or molybdenum are chosen from non-lacunated, lacunary and substituted polyoxometalate salts comprising nickel and a metal M being tungsten or molybdenum, from Keggin, Dawson, Anderson, Strandberg, Preyssler, Allman-Waugh, Weakley-Yamase and Dexter-Silverton structures.

Preferably, said at least one polyoxometalate salt used according to the invention is chosen from the following polyoxometalate salts:

Ni _3.5 PW ₁₂ 04o.nH ₂ 0, Ni ₄ SiW ₁₁ 0 ₃₉ .nH ₂ 0, Ni ₃ PW ₁₁ Ni0 ₄ oH.nH ₂ 0, Νϊ ₂ Μθ7θ23.ηΗ ₂ 0, Ni ₂ SiMo ₁₂ 04o.nH ₂ 0,

Νί _2.5 ΡΜθ _{ΐ 2} θ4ο.ηΗ ₂ 0, Νί _3.5 ΡΜθι ₂ θ4ο.ηΗ ₂ 0, Ni ₄ SiMoii0 ₃₉ .nH ₂ 0, Νί ₃ ΡΜθι ι ιθ4οΗ.ηΗ ₂ 0, Ni ₂ Moio0 ₃₈ H ₄ Ni ₄ , NiMo ₆ 0 ₂₄ H ₆ Ni ₂ .

In the case where several catalysts chosen from polyoxometalate salts comprising nickel and a metal M being tungsten or molybdenum are used in the process according to the invention, said catalysts may be identical or different. In a preferred embodiment, a single catalyst selected from polyoxometalate salts is used in the process according to the invention.

The metal M being molybdenum or tungsten are advantageously at the oxidation state (V) or (VI) in said polyoxometalate salts. When at least one molybdenum or tungsten atom of said polyoxometalate is at the oxidation state (V), then said polyoxometalate is said to be partially reduced. Said partially reduced polyoxometalates are described in FR 2,749,778.

The polyoxometalate salts as described in the invention are prepared by any method known to those skilled in the art, in particular the methods described in patent applications US 2,547,380, FR 2,749,778 and FR 2,764,21. and FR 2.843.050. They are characterized in solution or in crystalline form, for example by NMR, polarography, UV, Raman and infrared spectroscopies, X-ray diffraction.

Process of transformation

According to the invention, the process for transforming the feed selected from lignocellulosic biomass and carbohydrates, alone or as a mixture, is carried out in a reaction vessel in the presence of at least one solvent, said solvent being water alone or in admixture with at least one other solvent, under a reducing atmosphere, and at a temperature between 50 ° C and 300 ° C, and at a pressure of between 0.5MPa and 20MPa. The process is therefore carried out in a reaction vessel comprising at least one solvent and wherein said feedstock is placed in the presence of the catalyst according to the invention.

According to the invention, the process according to the invention operates in the presence of at least one solvent, said solvent being water alone or mixed with at least one other solvent. In the case where said method according to the invention operates in the presence of water mixed with at least one other solvent, the solvent mixture comprises a mass content of water greater than 5% by weight and preferably greater than 30% by weight and very preferably greater than 40% by weight relative to the total mass of said mixture. In the case where said solvent is water mixed with at least one other solvent, said other solvent is preferably chosen from alcohols and glycols.

The alcohols are advantageously chosen from methanol, ethanol, propan-1-ol and isopropanol and preferably ethanol. The glycols are advantageously chosen from ethylene glycol, propylene glycol, 1,2-butanediol and 1,4-butanediol and preferably ethylene glycol.

According to a preferred embodiment, the process according to the invention operates in the presence of a mixture containing between 20 and 70% by weight of water and between 30 and 80% by weight of alcohol.

According to another preferred embodiment, the process according to the invention operates in the presence of a mixture containing between 20 and 70% by weight of water and between 30 and 80% by weight of glycol.

According to the invention, the process for converting said charge is carried out under a reducing atmosphere, preferably under a hydrogen atmosphere. Hydrogen can be used pure or as a mixture.

Preferably, said method according to the invention operates at a temperature between 80 ° C and 250 ° C, and at a pressure between 2MPa and 20MPa.

Generally the method can be operated according to different embodiments. Thus, the process can advantageously be carried out batchwise or continuously. It can be carried out in a closed reaction chamber or in a semi-open reactor.

The catalyst comprising one or more salts of polyoxometalates according to the invention is advantageously introduced into the reaction chamber in an amount corresponding to a mass ratio filler / catalyst (s) of between 1 and 1000, preferably between 1 and 500, preferably between 1 and 100, preferably between 1 and 50 and even more preferably between 1 and 25.

The feedstock is introduced into the process in an amount corresponding to a mass ratio solvent / feed of between 1 and 1000, preferably between 1 and 500 and more preferably between 5 and 100.

If a continuous process is chosen, the hourly mass velocity (mass feed rate / mass of catalyst (s)) is between 0.01 and 5 h ^-1 , preferably between 0.02 and 2 h ^-1 . If a batch process is chosen, the reaction time is between 10 minutes and 48 hours, preferably between 10 minutes and 24 hours.

According to a preferred embodiment, said catalyst comprising one or more polyoxometalate salts according to the invention undergoes a reducing heat treatment step, preferably before its use in the process according to the invention.

Said reducing heat treatment may advantageously be carried out ex situ or in situ. Preferably, it is carried out in situ. In a very preferred manner, said reducing heat treatment can be carried out before introducing the feedstock or in the presence of the feedstock and very preferably before introducing the feedstock into the reaction vessel. Said reducing heat treatment may advantageously be carried out under a reducing atmosphere and / or in the presence of a chemical reducing agent.

In the case where the reducing heat treatment is carried out under a reducing atmosphere, the reduction temperature is between 50 ° C. and 500 ° C., preferably between 150 ° C. and 300 ° C. and at a pressure of between 0.5 MPa and 20 MPa. preferably between 2MPa and 20MPa and for a period of 30 minutes to 48 hours, preferably 1 hour to 24 hours. The reducing heat treatment is preferably carried out under a hydrogen atmosphere.

In the case where the reducing heat treatment is carried out in the presence of a chemical reducing agent, the chemical reducing agent is chosen from all reducing species known to those skilled in the art.

Preferably, the chemical reducing agent is chosen from the family of hydride source compounds, stabilized or not, and the family of nitrogenous organic compounds.

In the case where the chemical reducing agent is chosen from the family of hydride source compounds, stabilized or not, said reducing agent is advantageously chosen from sodium hydride NaH, potassium hydride KH, hydride of lithium LiH, MgH ₂ magnesium hydride, CaH ₂ calcium hydride, TiH ₂ titanium hydride, CuH ₂ copper hydride, ZrH ₂ zirconium hydride, NaBH ₄ sodium borohydride, lithium borohydride LiBH ₄ , potassium borohydride KBH ₄ , sodium cyanoborohydride NaBH ₃ CN, sodium triacetylborohydride NaBH (OAc) ₃ , sodium triethylborohydride NaBH (Et) ₃ , lithium triethylborohydride LiBH (Et) ₃ , sodium tributylborohydride NaBH [CH (CH ₃ ) C ₂ H ₅ ] 3, potassium tri-secbutylborohydride KBH [CH (CH ₃ ) C ₂ H ₅ ] ₃ , lithium tri-butylborohydride LiBH [CH (CH ₃ ) C ₂ H ₅ ] 3 Lithium (R or S) S-isopinocamphé-9-borabicyclo [3.3.1] nonylborohydride, lithium bicyclo [3.3.1] -9-borohydride, lithium dimethylaminoborohydride LiBH ₃ N (CH ₃ ) ₂ , lithium pyrrolidinoborohydride LiBH ₃ NC ₄ H ₈ , lithium morpholinoborohydride LiBH ₃ NOC ₄ H ₈ , sodium aluminohydride NaAlH ₄ , lithium aluminum hydride LiAlH ₄ , lithium aluminohexahydride Li ₃ AlH ₆ , sorting Lithium tert-butoxyaluminohydride LiAlH [OC (CH ₃ ) ₃ ] ₃ , diisobutylaluminum hydride AIH [(CH ₃ ) ₂ CHCH ₂ ] ₂ , sodium bis (2-methoxyethoxy) aluminohydride NaAIH ₂ (OCH ₂ CH ₂ OCH) ₃ ) ₂ , lithium tris (3-ethyl-3-pentyloxy) aluminohydride LiAlH [OC (C ₂ H ₅ ) ₃ ] ₃ , tributyltin hydride SnH [CH ₃ (CH ₂ ) ₃ ] ₃ , trihexyltin hydride SnH (C ₆ H ₁₁ ) ₃ , triphenyltin hydride SnH (C ₆ H ₅ ) ₃ , Tris [2- (perfluorohexyl) ethyl] tin hydride, triethylgermanium hydride GeH (C ₂ H ₅ ) ₃ , tributylgermanium hydride GeH (C ₃ H ₇ ) ₃ , hydride triphenylgermanium GeH (C ₆ H ₅ ) ₃ , triethylsilane SiH (C ₂ H ₅ ) ₃ , tris (trimethylsilyl) silane SiH [(CH ₃ ) ₃ Si] ₃ , choloromethyl (dimethyl) silane SiHCICH ₂ (CH ₃ ) ₂ , tris (trimethylsiloxy) silane SiH [(CH ₃ ) ₃ SiO] ₃ .

Most preferably, the chemical reducing agent is selected from NaBH ₄ , LiAlH ₄ and NaBH ₃ CN.

In the case where the chemical reducing agent is chosen from the family of nitrogenous organic compounds, said reducing agent is advantageously chosen from hydrazine, diethylhydroxylamine, hydroxylamine, and hydroquinone.

The chemical reducing agent is preferably diluted in a so-called chemical reduction solvent, the same or different from the reaction solvent. Preferably, the chemical reduction solvent is the reaction solvent.

The at least one reducing agent (s) is advantageously introduced into the reaction chamber in an amount corresponding to a mass ratio catalyst (s) / reducing agent (s) of between 1.5 and 1000. preferably between 5 and 1000, and preferably between 10 and 500.

In the case where the reducing heat treatment is carried out in the presence of a chemical reducing agent, the reduction temperature is between 10 ° C. and 300 ° C., preferably between 20 ° C. and 250 ° C. and at a pressure comprised between between 0.1 MPa and 20 MPa, preferably between 0.1 MPa and 10 MPa and for a period of 10 minutes to 48 hours, preferably from 1 hour to 40 hours. In the case where the reducing heat treatment is carried out in the presence of a chemical reducing agent, the atmosphere is preferably neutral, for example under dinitrogen, argon or helium.

The products obtained and their mode of analysis The products of the reaction of the transformation process according to the invention are mono- or polyoxygenated compounds. Said mono- or polyoxygenated compounds are soluble in water.

Said mono- or polyoxygenated compounds are advantageously constituted by monosaccharides and their derivatives, oligosaccharides, and also soluble polymers advantageously formed by successive combinations of the monosaccharide derivatives.

By monosaccharide is meant a carbohydrate composition C _n H ₂ nOn where n is greater than 2, obtained by partial or total hydrolysis of cellulose, or hemicellulose, or starch. Monosaccharides are simple sugars that are produced by depolymerization of cellulose and / or hemicellulose, such as, in particular, glucose, galactose, mannose, xylose, fructose, etc.

Derivatives of monosaccharides and oligosaccharides are products which can be obtained for example by dehydration, isomerization, reduction or oxidation:

- Alcoholic sugars, alcohols and polyols: in particular cellobitol, sorbitol, anhydrosorbitol, hexanetetrol, hexanetriols, hexanediols, xylitol, pentanetetrolols, pentanetriols, pentanediols, erythritol, butanetriols , butanediols, glycerol, 1,3-propanediol, propylene glycol, ethylene glycol, hexanols, pentanols, butanols, propanols, ethanol, etc.

monocetones, polyketones: hydroxyacetone, 2,5-hexanedione ...

carboxylic acids and their esters, lactones: formic acid, alkyl formates, acetic acid, alkyl acetates, hexanoic acid, alkyl hexanoates, levulinic acid, alkyl levulinates, lactic acid, alkyl lactates, glutaric acid, alkyl glutarates, 3-hydroxypropanoic acid, 3-hydroxybutyrolactone, γ-butyrolactone, γ-valerolactone cyclic ethers: for example tetrahydrofuran (THF), 3-methyltetrahydrofuran (Me-THF) and its positional isomers, 2,4-dimethyltetrahydrofuran and its positional isomers, tetrahydropyran-2-methanol and its isomers of position.

furans: furan-2,5-dicarboxylic acid, 5- (hydroxymethyl) furfural acid, furfural ...

Soluble polymers are all products resulting from the condensation between monosaccharides, oligosaccharides and / or monosaccharide derivatives.

EXAMPLES The following examples illustrate the present invention without, however, limiting its scope.

In the examples below, phosphotungstic and silicotungstic acids, ammonium metatungstate, oxalic acid, barium hydroxide, nickel sulfate, sodium borohydride are commercial products and used without further purification. At the end of the reaction, the reaction medium is removed and centrifuged. The reaction liquid is then analyzed by gas phase chromatography and high pressure liquid chromatography (HPLC) using refractometry to determine the content of conversion products of the aqueous solution.

Solid oxalic acid is added to a solution of 0.05 M ammonium metatungstate (NH 4) ₆ H ₂ W ₁₂ 0 ₄ 0. The ammonium oxalate precipitates and is removed from the reaction medium by filtration. A stoichiometric amount of barium hydroxide is added to the filtrate. The barium salt of polyoxometalate Ba ₃ H ₂ W ₁₂ O ₄ o precipitates and is filtered. This salt is resuspended in aqueous solution and three equivalents of nickel sulfate are added. The nickel salt of the polyoxometalate Ni ₃ H ₂ W ₁₂ 0 ₄ o goes into solution and the barium sulfate precipitates. Example 2 Preparation of the Lacunar Polvoxometallate Salt Catalyst of Keqqin N SiWnOaQ Structure nHpO (C2)

In a beaker, solid Ba (OH) ₂ (1.1 g, 5.81 mmol) is added to a 0.1 M aqueous solution of hydrated silicotungstic acid H ₄ SiW ₁₂ 04o.31 H ₂ O (15 ml). , 5 g, 1.45 mmol) at room temperature. The solution becomes whitish with the dissolution of Ba (OH) ₂ . Solid NiSO ₄ (1.25 g, 5.81 mmol) is then added. The reaction mixture is stirred for 3 hours at room temperature before standing for 2 hours. The white precipitate is then filtered to obtain a clear green apple filtrate. After evaporation of the water in air, a green solid is obtained (3.80 g, 76%). Example 3: Preparation of salt catalyst polvoxométallate substituted structure Keqqin NiaPWnNiainH.n _H? 0 (C3)

In a beaker, solid Ba (OH) ₂ (1 g, 5.25 mmol) is added to an aqueous solution of phosphotungstic acid hydrate H ₃ PW ₁₂ 0 ₄ o.24 H ₂ O at 0.1 mol / L ( 15 mL, 5 g, 1.5 mmol) at room temperature. The solution becomes whitish with the dissolution of Ba (OH) ₂ . Solid NiSO ₄ (1. 577 g, 6 mmol) is then added. The reaction mixture is stirred for 3 hours at room temperature before standing for 2 hours. The white precipitate is then filtered to obtain a clear green apple filtrate. After evaporation of the water in air, a green solid is obtained (4.02 g, 78%).

Example 4 Transformation of the Cellulose Using the Catalyst C1 Example 4 relates to the conversion of the cellulose from the catalyst C1 whose preparation is described in Example 1 for the production of mono- and polyoxygenated products.

In a 100 ml autoclave, the catalyst C1 (0.2 g) is solubilized in 25 ml of previously degassed water. The sodium borohydride NaBH ₄ (9.6 mg) is then added and the reaction medium is then stirred for 16 hours under 5 bar of nitrogen at 25 ° C.

The weight ratio catalyst / reducing agent is 21.

After returning to atmospheric pressure, the cellulose (0.65 g) is directly introduced. The weight ratio solvent / filler is 40. The mass ratio filler / catalyst is 3.25. A pressure of 2.5MPa of hydrogen is applied and the autoclave is heated at 230 ° C. After 6 hours of reaction _, the reaction medium is cooled and is analyzed by gas phase chromatography (GC). The majority products are ethylene glycol and propylene glycol at 1, 8 and 0.9 g / L respectively. No formation of humins is detected and the unconverted cellulose is removed by filtration. Example 5 Transformation of the Cellulose Using the Catalyst C1

Example 5 relates to the conversion of cellulose from catalyst C1 whose preparation is described in Example 1 for the production of mono- and polyoxygenated products.

In a 100 ml autoclave, the catalyst C1 (0.2 g) is solubilized in 25 ml of a mixture of 50/50 weight of water and ethanol degassed beforehand. The sodium borohydride NaBH ₄ (9.6 mg) is then added and the reaction medium is then stirred for 16 hours under 5 bar of nitrogen at 25 ° C.

The weight ratio catalyst / reducing agent is 21.

After returning to atmospheric pressure, the cellulose (0.65 g) is directly introduced. A pressure of 2.5 MPa of hydrogen is applied and the autoclave is heated to 230 ° C. The weight ratio solvent / filler is 40. The mass ratio filler / catalyst is 3.25. After 6 hours of reaction _, the reaction medium is cooled and is analyzed by gas phase chromatography (GC). The majority products are ethylene glycol and propylene glycol at 2.1 and 0.4 g / L respectively. No formation of humins is detected and the unconverted cellulose is removed by filtration.

Example 6 Transformation of the Cellulose Using the Catalyst C2

Example 6 relates to the conversion of cellulose from catalyst C2 whose preparation is described in Example 2 for the production of mono- and polyoxygenated products. In a 100 mL autoclave, the catalyst C2 (0.2 g) is solubilized in 25 mL of previously degassed water. The sodium borohydride NaBH ₄ (9.6 mg) is then added and the reaction medium is then stirred for 16 hours under 5 bar of nitrogen at 25 ° C.

The weight ratio catalyst / reducing agent is 21. After returning to atmospheric pressure, the cellulose (0.65 g) is directly introduced. A pressure of 2.5 MPa of hydrogen is applied and the autoclave is heated to 230 ° C. The weight ratio solvent / filler is 40. The mass ratio filler / catalyst is 3.25. After 6 hours of reaction _, the reaction medium is cooled and is analyzed by gas phase chromatography (GC). The majority products are ethylene glycol and propylene glycol at 2.4 and 1.3 g / l respectively. No formation of humins is detected and the unconverted cellulose is removed by filtration.

Example 7 Transformation of the Cellulose Using the Catalyst C2

Example 7 relates to the conversion of cellulose from catalyst C2 whose preparation is described in Example 2 for the production of mono- and polyoxygenated products.

In a 100 mL autoclave, the catalyst C2 (0.2 g) is solubilized in 25 mL of a 50/50 weight mixture of water and ethanol degassed beforehand. The sodium borohydride NaBH ₄ (9.6 mg) is then added and the reaction medium is then stirred for 16 hours under 5 bar of nitrogen at 25 ° C.

The weight ratio catalyst / reducing agent is 21.

After returning to atmospheric pressure, the cellulose (0.65 g) is directly introduced. A pressure of 2.5 MPa of hydrogen is applied and the autoclave is heated to 230 ° C. The solvent / filler mass ratio is 40. The mass ratio of filler / catalyst is 3.25. After 6 hours of reaction _, the reaction medium is cooled and is analyzed by gas phase chromatography (GC). The majority products are ethylene glycol and propylene glycol at 4.2 and 0.1 g / L respectively. No formation of humins is detected and the unconverted cellulose is removed by filtration.

Example 8 Transformation of the Cellulose Using the C3 Catalyst Example 8 relates to the conversion of the cellulose from the C3 catalyst, the preparation of which is described in Example 3 for the production of mono- and polyoxygenated products. In a 100 ml autoclave, the C3 catalyst (0.2 g) is solubilized in 25 ml of previously degassed water. The sodium borohydride NaBH ₄ (9.6 mg) is then added and the reaction medium is then stirred for 16 hours under 5 bar of nitrogen at 25 ° C.

The weight ratio catalyst / reducing agent is 21. After returning to atmospheric pressure, the cellulose (0.65 g) is directly introduced. A pressure of 2.5 MPa of hydrogen is applied and the autoclave is heated to 230 ° C. The weight ratio solvent / filler is 40. The mass ratio filler / catalyst is 3.25. After 6 hours of reaction _, the reaction medium is cooled and is analyzed by gas phase chromatography (GC). The majority products are ethylene glycol and propylene glycol at 4.9 and 2.9 g / L respectively. No formation of humins is detected and the unconverted cellulose is removed by filtration.

Example 9 Transformation of the Cellulose Using the C3 Catalyst

Example 9 relates to the conversion of cellulose from catalyst C3, the preparation of which is described in Example 3 for the production of mono- and polyoxygenated products.

In a 100 mL autoclave, the catalyst C3 (0.2 g) is solubilized in 25 mL of a 50/50 weight mixture of water and ethanol degassed beforehand. The sodium borohydride NaBH ₄ (9.6 mg) is then added and the reaction medium is then stirred for 16 hours under 5 bar of nitrogen at 25 ° C. The weight ratio catalyst / reducing agent is 21.

After returning to atmospheric pressure, the cellulose (0.65 g) is directly introduced. A pressure of 2.5 MPa of hydrogen is applied and the autoclave is heated to 230 ° C. The weight ratio solvent / filler is 40. The mass ratio filler / catalyst is 3.25. After 6 hours of reaction _, the reaction medium is cooled and is analyzed by gas phase chromatography (GC). The majority products are ethylene glycol and propylene glycol at 10.3 and 0.4 g / L respectively. No formation of humins is detected and the unconverted cellulose is removed by filtration. Example 10 Transformation of Glucose in Semi-Continuous Mode Using the C3 Catalyst

Example 10 relates to the conversion of glucose from catalyst C3, the preparation of which is described in Example 3 for the production of mono- and polyoxygenated products.

After returning to atmospheric pressure, a first addition of glucose (0.65 g) is directly introduced. A pressure of 2.5 MPa of hydrogen is applied and the autoclave is heated to 230 ° C. The weight ratio solvent / filler is 40. The mass ratio filler / catalyst is 3.25. After 1 hour of reaction _, the reactor is depressurized and a second addition of glucose (0.65 g) is carried out. The reactor is repressurized with 2.5 MPa of hydrogen. After a further hour of reaction _, the reactor is depressurized again and a third glucose addition (0.65 g) is performed. The reactor is repressurized with 2.5 MPa of hydrogen. After a new reaction time, the reaction medium is cooled and analyzed by gas phase chromatography (GC). The majority products are ethylene glycol and propylene glycol at 32.5 and 1.2 g / L respectively. No formation of humins is detected.

Unexpectedly, the use of homogeneous catalysts according to the invention is therefore effective for the conversion of cellulose and carbohydrates into mono- and polyoxygenated products without formation of humins and avoiding an additional step of separation between residual solids that may be a heterogeneous catalyst, humins, lignin and / or unconverted cellulose. Example 1 1 (Comparative): Transformation of the Cellulose Using the Catalyst System Ni of Ranev + H3PW12O40.xH2O

Example 11 relates to the conversion of cellulose for the production of mono- and polyoxygenated products from a catalyst system composed of heterogeneous nickel and tingene.

The amounts of Ni and W present in the suspension correspond to those present in the catalyst C3 and the reaction medium corresponds to that described in Example 8.

In a 100 mL autoclave, the Raney Ni (0.036 g) is suspended in 25 mL of degassed water. Phosphotungstic acid H3PW12O40, xH2O (0.18 g) is then added and the mixture is stirred for 16 hours under 2.5 MPa hydrogen at 25 ° C.

After returning to atmospheric pressure, the cellulose (0.65 g) is directly introduced. A pressure of 2.5 MPa of hydrogen is applied and the autoclave is heated to 230 ° C. The solvent / filler mass ratio is 40. The mass ratio filler / catalyst is 3. After 6 hours of reaction, the reaction medium is cooled and analyzed by gas phase chromatography (GC). The major products are ethylene glycol and mono-alcohols (Ethanol, 1-propanol, 1-butanol) at 1, 5 and 1, 3 g / L, respectively.

Example 12 (Comparative): Transformation of Cellulose Using the Ranev Catalyst System + H3PW12O40.xH2O Example 12 relates to the conversion of cellulose for the production of mono- and polyoxygenated products from a composite catalyst system heterogeneous Nickel and Tunsgten.

The amounts of Ni and W present in the suspension correspond to those present in the catalyst C3 and the reaction medium corresponds to that described in Example 9. In a 100 ml autoclave, the Raney Ni (0.036 g) is put in suspension in 25 mL of a 50/50 weight mixture of water and ethanol degassed beforehand. Phosphotungstic acid H3PW12O40, xH2O (0.18 g) is then added and the mixture is stirred for 16 hours under 2.5 MPa hydrogen at 25 ° C. After returning to atmospheric pressure, the cellulose (0.65 g) is directly introduced. A pressure of 2.5 MPa of hydrogen is applied and the autoclave is heated to 230 ° C. The weight ratio solvent / filler is 40. The mass ratio filler / catalyst is 3. After 6 h of reaction, the reaction medium is cooled and is analyzed by gas phase chromatography (GC) the majority products are ethylene glycol, mono-alcohols (1-propanol, 1-butanol) and ethylene glycol monoethyl ether at 0.8, 0.7 and 0.5 g / L, respectively.

Examples 11 and 12 compare the catalytic activity of a catalytic system composed of nickel and tungsten with the activity of the catalysts C1, C2, and C3 according to the invention. The results of conversion of said catalytic system compared with the results obtained in Examples 8 and 9 with the catalyst C 3 demonstrate that the catalysts according to the invention are more effective than catalytic systems consisting of the same amounts of Ni and W and used in the same operating conditions.

Claims

A method of transforming a filler selected from lignocellulosic biomass and carbohydrates, alone or in admixture, into mono- or polyoxygenated compounds, wherein said filler is contacted with a catalyst comprising one or more polyoxometalate salts comprising nickel and a metal M being tungsten or molybdenum, in the presence of at least one solvent, said solvent being water alone or in admixture with at least one other solvent, under a reducing atmosphere, and at a temperature between 50 ° C and 300 ° C, and at a pressure between 0.5MPa and 20MPa, wherein, said polyoxometalate salt or salts comprising nickel and a metal M being tungsten or molybdenum, correspond to the general formula (I )

Ni _x M _y O _z H _h A _a M ' _m C _c . nH ₂ 0 (I) in which

• Ni is nickel,

• M is tungsten or molybdenum,

• O is oxygen,

• H is hydrogen,

A is selected from phosphorus, silicon, boron, germanium, arsenic,

M 'is a metallic element other than nickel and tungsten when M is tungsten and M' is a metallic element other than nickel and molybdenum when M is molybdenum, said metal element being selected from molybdenum, tungsten , aluminum, zinc, cobalt, vanadium, niobium, tantalum, iron and copper,

X is between 1 and 20,

• is between 4 and 80,

• a is greater than or equal to 0,

• m is greater than or equal to 0,

Z is between 20 and 400, H is between 0 and 20,

N is between 0 and 200,

• c is greater than or equal to 0,

• c, a, m, h, x, y, z and n are integers or decimals when stoichiometry and salt neutrality dictate it.

2. Method according to claim 1 wherein said catalyst (s) is (are) chosen from polyoxometalate salts comprising nickel and a metal M being tungsten or molybdenum, corresponding to the general formula (I). )

Ni _x M _y O _z H _h A _a M ' _m C _c . nH ₂ 0 (I) in which

• Ni is nickel,

• M is tungsten,

• O is oxygen,

• H is hydrogen,

A is selected from phosphorus and silicon,

• C is nickel,

X is between 1 and 10,

• is between 4 and 50,

• a is equal to 0, 1 or 2,

• m is greater than or equal to 0,

Z is between 20 and 200,

H is between 0 and 10,

N is between 0 and 100,

• c is greater than or equal to 0,

3. A method according to one of claims 1 to 2 wherein said one or more polyoxometalates salts used according to the invention are chosen from the following polyoxometalates salts: \ ₃ H ₂ \ ^ N ₂ O ₄₀ · nH ₂ O, Ni ₂ SiW ₁₂ 0 ₄ o.nH ₂ 0, Ni ₃ SiW ₁₂ 0 ₄ o.nH ₂ 0, Ni4SiW ₁₂ 04o.nH20, Ni ^ PW ^ C o.nl- ^ O, Ni ₂ , ₅ PW ₁₂ 04o.nl -l ₂ 0, ₁₂ 0 ₄ Ni3,5PW o.nH ₂ 0, Ni ₄ SiW ₃₉ _{1 1} 0 _There .nH ₂ 0, NiaPWn NiO ^ H.nHsO, Νί ₂ Μθ ₇ θ ₂₃ .ηΗ ₂ 0, Ni ₂ SiMo ₁₂ 0 ₄ o.nH ₂ 0,

Ni ₃ SiMoi ₂ 0 ₄ o.nH ₂ 0, Ni4SiMoi ₂ 04o.nH ₂ 0, Νί _{1, 5} ΡΜθ _{ΐ 2} θ4ο.ηΗ ₂ 0, Νί _2.5 ΡΜθ _{ΐ 2} θ4ο.ηΗ ₂ 0, Νί _3.5 ΡΜο ₁₂ θ4ο.ηΗ ₂ θ, Ni ₄ SiMo _{1 1} 0 ₃₉ .nH ₂ 0, Ni ₃ PMo ₁₁ Ni0 ₄ oH.nH ₂ 0, Ni ₂ Mo ₁₀ O ₃₈ H ₄ Ni ₄ ,

4. Method according to claim 3 wherein in the case where said method according to the invention operates in the presence of water in admixture with at least one other solvent, the solvent mixture comprises a mass content in water greater than 40% relative to to the total mass of said mixture.

5. Method according to claim 4 wherein said other solvent is preferably selected from alcohols among methanol, ethanol, propan-1-ol and isopropanol and glycols selected from ethylene glycol, propylene glycol 1,2-butanediol and 1,4-butanediol.

6. Method according to one of claims 1 to 5 wherein said catalyst comprising one or more salts of polyoxometalates is introduced into the reaction chamber in an amount corresponding to a mass ratio filler / catalyst (s) between 1 and 1000.

7. Method according to one of claims 1 to 6 wherein the filler is introduced into the process in an amount corresponding to a weight ratio solvent / charge of between 1 and 1000.

8. Method according to one of claims 1 to 7 wherein said catalyst comprising one or more salts of polyoxometalates undergoes a reducing heat treatment step before its use in the process according to the invention.

9. The method of claim 8 wherein said reducing heat treatment is performed before the introduction of the feed into the reaction chamber.

Method according to one of claims 8 or 9 wherein said reducing heat treatment is carried out under a reducing atmosphere and / or in the presence of a chemical reducing agent.

Process according to Claim 10, in which in the case where the chemical reducing agent is chosen from the family of hydride source compounds, stabilized or not, said reducing agent is chosen from sodium hydride NaH, potassium hydride. KH, lithium hydride LiH, MgH ₂ magnesium hydride, CaH ₂ calcium hydride, TiH ₂ titanium hydride, CuH ₂ copper hydride, ZrH ₂ zirconium hydride, sodium borohydride, NaBH _4, lithium borohydride LiBH _4, potassium borohydride KBH _4, sodium cyanoborohydride, NaBH ₃ CN, sodium triacétylborohydrure NaBH (OAc) _3, sodium triethylborohydride NaBH (Et) _3, the triethylborohydride lithium LiBH (Et) ₃ , sodium tri-secbutylborohydride NaBH [CH (CH ₃ ) C ₂ H ₅ ] ₃ , potassium tris-butylborohydride KBH [CH (CH ₃ ) C ₂ H ₅ ] ₃ , sorting Lithium cis-butylborohydride LiBH [CH (CH ₃ ) C ₂ H ₅ ] ₃ , lithium B-isopinocamphenyl-9-borabicyclo [3.3.1] nonylborohydride (R or S), lithium bicyclo [3.3.1] -9-borohydride, lithium dimethylaminoborohydride LiBH ₃ N (CH ₃ ) ₂ , lithium pyrrolidinoborohydride LiBH ₃ NC ₄ H ₈ , lithium morpholinoborohydride LiBH ₃ NOC H ₈ , sodium aluminohydride NaAIH ₄ , lithium aluminum hydride LiAlH ₄ , lithium aluminohexahydride Li ₃ AlH ₆ , lithium tri-tertbutoxyaluminohydride LiAlH [OC (CH ₃ ) ₃ ] ₃ , hydride of diisobutylaluminum AIH [(CH ₃ ) ₂ CHCH ₂ ] ₂ , sodium bis (2-methoxyethoxy) aluminohydride NaAIH ₂ (OCH ₂ CH ₂ OCH ₃ ) ₂ , lithium tris (3-ethyl-3-pentyloxy) aluminohydride LiAIH [OC (C ₂ H ₅ ) ₃ ] ₃ , tributyltin hydride SnH [CH ₃ (CH ₂ ) ₃ ] ₃ , trihexyltin hydride SnH (C ₆ H ₁₁ ) ₃ , triphenyltin hydride SnH (C ₆ H ₅ ) ₃ , Tris [2- (perfluorohexyl) ethyl] tin hydride, triethylgermanium hydride GeH (C ₂ H ₅ ) ₃ , tributylgermanium hydride GeH (C ₃ H ₇ ) ₃ , triphenylgermanium hydride GeH (C ₆ H ₅ ) ₃ , triethylsil SiH (C ₂ H ₅ ) ₃ , tris (trimethylsilyl) silane SiH [(CH ₃ ) ₃ Si] ₃ , choloromethyl (dimethyl) silane SiHCICH ₂ (CH ₃ ) ₂ , tris (trimethylsiloxy) silane SiH [( CH ₃ ) ₃ SiO] ₃ .

The process of claim 11 wherein the chemical reducing agent is selected from NaBH ₄ , LiAlH ₄ and NaBH ₃ CN.

13. The method of claim 10 wherein in the case where the chemical reducing agent is selected from the family of nitrogenous organic compounds, selected from hydrazine, diethylhydroxylamine, hydroxylamine, and hydroquinone.

14. Method according to one of the preceding claims operating at a temperature between 80 ° C and 300 ° C, and at a pressure between 2MPa and 20MPa.